1. Field of the Invention
The present invention relates to improvement in or relating to an engine including a motorized throttle valve and further including a cylinder head joined to an upper end face of a cylinder block having three or more cylinders disposed in series to each other. A head cover is connected to an upper end face of the cylinder head with a valve system accommodated in a valve chamber defined by and between the cylinder head and the head cover and including first and second camshafts extending in parallel to each other. A plurality of throttle bodies are disposed at a side of the valve chamber and corresponding to the cylinders. An electric motor is connected to a valve shaft for throttle valves, which open and close intake paths of the throttle bodies, and are configured to drive the throttle valves to open or close.
2. Description of Background Art
An engine including a motorized throttle valve is disclosed in Japanese Patent No. 4476421.
In the engine including a motorized throttle valve disclosed in Japanese Patent No. 4476421, an electric motor is attached to one side face of an engine main body spaced from a throttle body such that output power of the electric motor is transmitted to a throttle valve through a control cable (Bowden wire). Therefore, while the throttle body and the cylinder head can be disposed in a neighboring relationship with each other without interfering with the electric motor, a transmission delay of the output power of the electric motor to the throttle valve occurs, due to the presence of the control cable (Bowden wire). Therefore, the opening and closing responsibility of the throttle valve is not good.